Big Clunk

This one has me puzzled.

Friday night while driving I was going down a slight hill and while breaking took a hard left turn. I heard a clunk from the right hand side of the vehicle., seemed unusual but dismissed it as something on the road. Then less than 10 minutes later while breaking fairly hard and turning left another quite loud clunk from the right hand side. Okay there was definitely nothing on the road or pothole to have caused that.

Initial thought was radius arm bushing or maybe a ball joint.

I took a good look Sunday. Lifted it up, ball joints are tight, wheel bearing seems good, wheel not loose and I can't get any movement at the radius arm bushing and to my surprise they actually look in pretty good shape.

For the heck of it I checked the drivers side. I found some play in that wheel. The play turned out to be related to the bearing not being seated. The lock hardware was in there properly so it didn't move, just seemed like it never had been seated all the way.

I also found that the slide pins on the caliper had jammed up and that was causing serious pressure by one pad when brakes were released. Fixing that solved my braking pull mystery.

I do not think these issues on the driver side wheel were related to the clunk on the passenger side.

I have not been able to reproduce the problem while driving. The only thing that seems off to me is when I look at the drivers side the front wheel seems well centered in the wheel well. When I look at the passenger side the wheel seems to be back in the wheel well, maybe a half inch off of center such that the gap in the rear is an inch smaller than the gap towards the front. But far I know it could have been that way before.

Anyone have any thoughts? I am fairly confident in my checking the ball joints. Checking the radius arm bushings I am not so confident so if anyone has any tricks for that is appreciated.

As far as where the wheel sits, seems to me that is pretty much controlled by the radius arm. Or is there something else that could affect that?

Could the point where the radius arm connects to the frame have shifted back? Grasping at straws here. Nothing looks like it moved. Could there be something loose on the frame that could have shifted?

Oh ad just as an aside, what is the best stuff to put on the brake caliper slide pins. These were new pins from when I replaced the caliper. They had whatever the original goo was that seems have just turned into glue.

I've had clunking on my front end and aside from having the wheel come off once due to a mashed bearing...the caliper pins where seized on both sides. Who knew part of regular maintenance is to grease the sliders every six months or more?

I found some brake grease in a parts store that was purple and worked great...I still have the tube but something corrosive got on it at some point and I could not see the brand name...but pretty much any brake grease will work there...as long as it can stand up to the temps it is fine.

The pins are relatively resilient and will be fine as long as the rubber doesn't melt or break free...give them a squeeze with some pliers just to check the play.

EDIT: Oh, and you're correct about the radius arms dictating the distance forward or back...you can measure them to see if there is a difference. If someone replaced them at some point then they may have used mismatched parts...I think the thickness of the rubber may affect the distance and may also be susceptible to too much torque...

I'd also suspect a slight difference might not be noticeable but tire wear might be an issue...they just don't track right.

in my experience, a clunk while turning and braking simultaneously is almost always because of a loose wheel bearing. checking for play in the radius arm bushing certainly wouldn't hurt, especially since that side is subject to exhaust heat. as far as the brake slides/pins, i use sil-glyde on any moving brake hardware.

ab_slack said:

As far as where the wheel sits, seems to me that is pretty much controlled by the radius arm. Or is there something else that could affect that?

Click to expand...

On mine, that was caused by a bad radius arm bushing.

One thing this BII has taught me is that bushings can look "ok" and still be bad.

JerryC said:

On mine, that was caused by a bad radius arm bushing.

One thing this BII has taught me is that bushings can look "ok" and still be bad.

Click to expand...

I was wondering if it is possible to adjust the position by adjusting the nuts on the radius bushing. is there a nut on both sides or just the one? I guess I could just look.

Just one. Pull the big nut and you'll be able to see if the bushings are bad.
They could be eaten up where you cant see it and it is banging the RA bracket.

radius arm bushings

I have replaced many radius arm bushings. They can look good and still be bad. Take a pry bar and wedge it between the large rear washer and the frame, try to move it. Or have someone drive the truck forward and back and hit the brakes, if the arm moves more the 1/8th of and inch it is bad. But if its making a clunk it will move a lot. Also check the pivot arm bushings if you have independent suspension. Those will give you negative camber and noise.

My new to me 87 B2 , is doing somewhat the same thing , a clunk when braking , it is long overdue for some poly bushings with 180k miles on the factory bushings.

I will take another look...I would think that if they were bad I should have been able to cause them to move by levering on them